Andrew Quint Reviews the Unique BACCH-SP Stereo Purifier

[Justdafactsmaam]

The thing I notice mostly about ORC is that I thought my system was sounding pretty good prior now I realize I was wrong…so wrong. The effect is dramatic enough that it seems that somehow BACCH now makes thing worse if it’s unused in the audio chain.

That’s been the consensus so far. What are your impressions on how it affects the bass?

 

[Gwreck]

That’s been the consensus so far. What are your impressions on how it affects the bass?it does not seem to take away any bass overall but it does seem to make it a bit clearer.

 

[jimbill]

I installed it yesterday with the help of my daughter, never would have been able to do it on my own. Mac is very new to me.

First impression is richness of sound. When I bypass it, recordings get not just narrower but also thinner. The frequency response graph is very close to flat.

I agree, I can't imagine ever listening to my system without it. It is the best thing since speaker upgrading. Spending big bucks on anything else in your system will never make as big an impact.

I feel like I've lost some of the soundstage width. I'm still getting instruments positioned wide of the speakers, just not as wide. I've got a help request into Edgar to check my settings.

 

[onion]

I have mixed feelings about it. In terms of rendering a 3d sound field, it is superb. I'm getting around 8.5dB XTC which is similar or slightly better than before. For me the soundstage has expanded.

But I feel the bass is lacking. I'm not sure how to play around with the settings in ORC to get a downward sloping frequency response from 20 - 120Hz.

And it attenuates the sound by nearly 7dB in my system (Genelec Ones + W371). Whereas previously the sound could reach 105dB at the listening position with the GLM volume control set to -25dB, now it struggles to reach over 100dB with the GLM volume control set to -7dB

 

[kthulhutu]

I have mixed feelings about it. In terms of rendering a 3d sound field, it is superb. I'm getting around 8.5dB XTC which is similar or slightly better than before. For me the soundstage has expanded.

But I feel the bass is lacking. I'm not sure how to play around with the settings in ORC to get a downward sloping frequency response from 20 - 120Hz.

And it attenuates the sound by nearly 7dB in my system (Genelec Ones + W371). Whereas previously the sound could reach 105dB at the listening position with the GLM volume control set to -25dB, now it struggles to reach over 100dB with the GLM volume control set to -7dB

EQ to taste in the output plugin?

 

[ccw]

Head tracking like the Apple Spatial Audio which also make 3D audio besides Sony 360, uses head tracking for HP so that the sound stage is not static when you rotate the head. This generally applies real time filter to change the sound so that the scene to head rotation or movement is maintained. For loudspeakers such application can be used for multiple users with beam forming speakers.

Reading from the BACCH website, head tracking also meant to capture the image of your head for XTC calculation. They differentiate it when they talk about uBACCH and said that it is without head tracking and therefore users must feed in the values. So does head tracking here meant head measurement?

There was also a Hungarian Engineering students survey of various XTC and put another DSP as the best. So it all depends who is making the claim.

For what it is worth, BACCH is the first XTC which managed to get the attention of Stereophiles magazine unlike others. I am unfortunate that UBACCH didn’t work with my system but to judge if one is better or not all you need is judge the sound yourself by a simple method.

Use a binaural microphone and record the playback of your system with only one channel playing at one time. You will now have two recordings and remove the other channel from each and merge to a new stereo track. The track that you have is the best crosstalk cancelled playback that even BACCH cannot match, Now compare these recording samples with various crosstalk DSP and judge for yourself which is the best. In fact, these method is precise that it can even tell if BACCH or other DSP causing phase issues or projecting the sound which is beyond actual crosstalk cancellation. Alternatively, you can use headphones but you have to do some guess work for tonal coloration due to lack of pinna’s role. Neumann K100 comes with generic correction or you can also use one and do your own measurements. If you do these you would know how good or bad is a DSP.

Can you go into more detail about why UBACCH didn’t work in your system?

 

[jimbill]

I have mixed feelings about it. In terms of rendering a 3d sound field, it is superb. I'm getting around 8.5dB XTC which is similar or slightly better than before. For me the soundstage has expanded.

But I feel the bass is lacking. I'm not sure how to play around with the settings in ORC to get a downward sloping frequency response from 20 - 120Hz.

And it attenuates the sound by nearly 7dB in my system (Genelec Ones + W371). Whereas previously the sound could reach 105dB at the listening position with the GLM volume control set to -25dB, now it struggles to reach over 100dB with the GLM volume control set to -7dB

How does the bass and volume compare when you bypass ORC?

I'm getting XTC values of around 16dB left and 12dB right. I can't figure out why the difference.

 

[slaweks]

How does the bass and volume compare when you bypass ORC?

I'm getting XTC values of around 16dB left and 12dB right. I can't figure out why the difference.

I also have a similar problem. My solution, I am not sure what Edgar would say for this, is to turn your head a bit left during the measurements.

 

[Justdafactsmaam]

How does the bass and volume compare when you bypass ORC?

I'm getting XTC values of around 16dB left and 12dB right. I can't figure out why the difference.

Is the room and setup completely symmetrical?

 

[Dialectic]

I installed it yesterday with the help of my daughter, never would have been able to do it on my own. Mac is very new to me.

First impression is richness of sound. When I bypass it, recordings get not just narrower but also thinner. The frequency response graph is very close to flat.

I agree, I can't imagine ever listening to my system without it. It is the best thing since speaker upgrading. Spending big bucks on anything else in your system will never make as big an impact.

I feel like I've lost some of the soundstage width. I'm still getting instruments positioned wide of the speakers, just not as wide. I've got a help request into Edgar to check my settings.

Welcome to the bleeding edge

 

[STC]

Can you go into more detail about why UBACCH didn’t work in your system?

It also didn’t work with another person using the same speakers like mine. My guess is because the speakers were placed in a configuration known as Ambiodipole, i.e., that is closely placed speakers confirming to the original XTC idea.

Furthermore, in the uBACCH website itself it says, and I quote “The result can come close to a measured custom BACCH (c-BACCH) filter if the speakers are well matched in frequency and phase response and the listening configuration/environment is symmetrical and balanced.” So it could be a combination of those.

 

[jimbill]

It also didn’t work with another person using the same speakers like mine. My guess is because the speakers were placed in a configuration known as Ambiodipole, i.e., that is closely placed speakers confirming to the original XTC idea.

Furthermore, in the uBACCH website itself it says, and I quote “The result can come close to a measured custom BACCH (c-BACCH) filter if the speakers are well matched in frequency and phase response and the listening configuration/environment is symmetrical and balanced.” So it could be a combination of those.

Also, are your speakers directional?

 

[STC]

Also, are your speakers directional?

They are Sound Labs Electrostatics speakers. These speakers were chosen among so many others for best cancellation which included the MBL Omni for the Ambiophonics institute. The setup for BACCH was done by Choueiri himself in 3 different pairs of Sound Labs at the institute but eventually got it working with Keele’s designed CBT speakers.

 

[Dialectic]

I too prefer the Olive curve in ORC.

I also realized that, although I had head tracking enabled for phases 1 and 2 of filter creation, I had somehow disabled ORC head tracking--but not BACCH head tracking--after I made the filters. It is enabled now with the new Olive curve ORC filter, and I am extremely impressed. The specificity of imaging clearly exceeds what is possible with BACCH alone.

I am also getting higher estimated XTC values than I was with the Katz filter.

More experimentation is needed, and with any luck, I won't wake the kids next time....

 

[Dialectic]

A question for other ORC users: when head tracking is engaged with ORC, are you supposed to see any animation in this window?

What do the highlighted (in the red rectangle) buttons do?

Many thanks

 

[onion]

A question for other ORC users: when head tracking is engaged with ORC, are you supposed to see any animation in this window?

View attachment 350981

What do the highlighted (in the red rectangle) buttons do?

Many thanks

I don't know - I did see the head animated at one time (with the animation matching my movements relative to the camera in real-time). But only once. Hopefully, Theoretica will publish a more comprehensive user guide

 

[slaweks]

I don't know - I did see the head animated at one time (with the animation matching my movements relative to the camera in real-time). But only once. Hopefully, Theoretica will publish a more comprehensive user guide

You need to click on the button "ORC Head Tracking Enabled"

 

[Dialectic]

You need to click on the button "ORC Head Tracking Enabled"

I didn't see any animation after I did that, and I definitely had head tracking enabled during both stages of filter creation.

 

[Dialectic]

I'm seeing the ORC animation now. The buttons I highlighted just change the view of the dummy in the ORC-HT window - no effect on the sound as far as I can tell.

I'm increasingly convinced--following lots of switching it on and off (not a blind test, but the effect is not subtle)--that ORC is a major advance.

 

[Gwreck]

I'm seeing the ORC animation now. The buttons I highlighted just change the view of the dummy in the ORC-HT window - no effect on the sound as far as I can tell.

I'm increasingly convinced--following lots of switching it on and off (not a blind test, but the effect is not subtle)--that ORC is a major advance.

My non-scientific opinion is that it makes my speakers, which I thought sounded amazing prior to ORC, sound broken without it.